Browsers

My recommendations:

macOS/iOS: Safari
other: Chrome

Versions of all "major" browsers:

browser β developer nightly platforms
Safari* Technology Preview Webkit macOS/iOS*, Linux (T.P. & Webkit on macOS & Linux only)
Chrome* β Dev Canary macOS/iOS*, Windows, Linux/Android
Opera* β Developer macOS/iOS*, Windows, Linux/Android
Firefox β Developer/Aurora Minefield macOS/iOS*, Windows, Linux/Android
Edge*‡ β Windows, iOS, Android (,macOS soon*)
 
‡ Replaced Internet Explorer:
Windows XPVista7,8,10
runs IE 89Edge

* originally developed the HTML renderer Webkit (based on KHTML) for Safari as open source.
  • The proxy browser UC Browser uses U3, based on Webkit.
  • Webkit on Linux is known as "Epiphany" or "Web".
  • iOS browsers are restricted by  to use Webkit.
Chrome uses Blink (Chromium), based by Google on Webkit.
  • Opera also uses Blink. So does Samsung Internet.
  • Edge is moving to Blink.

Mailers

My recommendations:

macOS/iOS: Mail
browser elsewhere: iCloud
browser w/o iCloud account: Gmail

(Don't even think about using one named after a tree.)